LITTLE ROCK, Ark. (AP) - Arkansas senators advanced a proposal Wednesday to ban most abortions if a fetal heartbeat is detected, a move that would prohibit the procedure as early as six weeks into a pregnancy, despite a warning from opponents that it would open the state up to legal challenges.

The Senate Public Health, Welfare and Labor Committee endorsed by a voice vote legislation that would require a test to detect a fetal heartbeat before an abortion is performed. If one is detected, a woman could not have an abortion, except in cases of rape, incest and if a mother's life is in danger.

The measure heads to a vote in the Republican-controlled Senate, where it's sponsored by 19 of the chamber's 35 members.

"I simply recognize that without a heartbeat, there is no life, and life must be protected," Sen. Jason Rapert, R-Conway, the bill's chief sponsor, told reporters after Wednesday's hearing.

Similar proposals have come up in other states but have faced complaints that it would run afoul of the U.S. Supreme Court's 1973 Roe v. Wade ruling that legalized abortion up until viability, usually at 22 to 24 weeks. Such legislation is pending in Mississippi and North Dakota, and one was debated but later sidetracked in Ohio last year.

Opponents of the Arkansas measure echoed similar complaints, vowing to challenge the ban in court if it becomes law.

"If this passes, you might as well write a check to the ACLU or Planned Parenthood because we will feel the necessity to go to court to protect the rights of women," Bettina Brownstein, an attorney for the ACLU of Arkansas, told the panel.

Rapert told the panel he believed the restriction would withstand any constitutional challenge, calling viability a "moving target" that has changed with advances in medicine since Roe v. Wade.

Under Rapert's bill, anyone who performs an abortion could face a Class D felony, punishable by up to six years in prison and a fine of up to $10,000. The woman seeking an abortion can't be charged under his bill.

Lori Williams, a women's health practitioner who opposed the restriction, told the committee that the only way a heartbeat could be detected under the bill would be through a vaginal probe ultrasound.

"This would require a woman to go through an invasive, medically unnecessary test that would be mandated by the Legislature," Williams told the panel as she showed them the type of probe that would be needed for the test.

Gov. Mike Beebe, a Democrat, told reporters he was reviewing the legislation and hadn't decided whether he would sign it into law if it reaches his desk.

"I think you've got to talk to a whole lot of legal folks to see what's legal, what complies with federal law and what doesn't, so we'll just wait and see on that," Beebe said.

Attorney General Dustin McDaniel's office would not say whether he believed the measure was constitutional.

"We have briefed the sponsors and leadership on our constitutional analyses and litigation strategies," said Aaron Sadler, a spokesman for McDaniel's office. "We expect the Legislature to pass many of these bills this session, and we will prepare for the litigation that will result."

The proposal is one of several new restrictions that abortion opponents plan to push in the Legislature, after an election last year that handed Republicans control of the state House and Senate. A day earlier, the House Public Health Committee rejected a proposal to ban abortions from being covered under the health insurance exchanges created through the federal health care law. The sponsor of that bill said he planned to bring it back before the committee.

The same House panel planned Thursday to consider legislation that would ban abortions at 20 weeks. Rapert said the two measures would complement each other since the 20-week ban does not include exemptions for rape or incest.